Andy Kirkpatrick has an excellent explanation of soft shells on his Psychovertical website, http://www.psychovertical.com/?thebestsoftshell
For my money, forget about anything with a laminated fabric, such as Powershield or Windstopper. These are the antithesis of both layering and softshell philosophy. They're to insulated to be a layering shell, and not breathable enough to be a softshell. I'm pretty sure there have been no replies from USERS on this thread defending them. It's true to say that these are the suburban fashion pieces. You put them on when you leave the house, wear them to watch the kids play soccer, and take them off when you get to the mall or work.
Stretch wovens such as Scoeller and Inertia are a completely different story. You put them on when you get up in the morning (assuming you didn't sleep in them) wear them all day and take them off (optional) when you go to bed at night. If it gets cold, you flip your hood up. If you don't have a hood, it's not a true softshell. On a six day trip in anything but summer, I'll generally take my pants off somewhere around day 2 or 3 to change underwear, and maybe again on day 4. Otherwise they stay on. They NEVER go in my pack.
Softshells do require a leap of faith to work well.
They require you to adjust from a lifetime of a layering.
They work best with just one THIN layer underneath. They don't work as a softshell when you wear a fleece underneath. This turns them into a heavyweight windproof.
They aren't magic- You can't substitute them for a puffy jacket with 3/4" of loft. To think you can is naivety at best, stupidity at worst.
They aren't magic- 30 min of heavy rain will wet them out. You need to decide if this is a problem for you. Options are to carry a hardshell, sit under a tarp for half an hour and watch the world change around you while you have lunch, or realise that if the front will move through fairly quickly, you won't be any wetter or colder in your softshell than you will be in your hardshell.
They excel at stop-go activity
They're heavy. This is the bottom line. They weigh more than a windshell and a baselayer. You need to decide whether this makes them worth carrying for you. I debate taking my MEC Ferrata Jacket every trip, but find that I wear it ALL the time, every time I take it. My MEC Schoeller pants are worn, every trip I don't plan on being in shorts from breakfast to dinner. Please believe me when I say that these are NOT a fashion item. Imagine the most embarrassing pair of nylon track pants your Dad wore in the 70s. Now add in hand patched crampon holes. All in a hideous schoolboy blue. Now you understand how good they must be to get me to wear them.
Rod